Microelectronic samples, such as silicon wafers, may be damaged during shipping, handling or production. For example, mechanical damage may cause defects in the crystalline structure of the wafer. Various methods have been developed for detecting crystalline defects.
For example, U.S. Pat. No. 6,782,076, whose disclosure is incorporated herein by reference, describes an X-ray topographic system, comprising an X-ray generator producing a beam of X-rays impinging on a limited area of a sample such as a silicon wafer. A solid-state detector is positioned to intercept the diffracted beam after transmission through or reflection from the sample and produces a digital image of the area on which the X-rays impinge. Relative stepping motion between the sample and the X-ray generator produces a series of digital images, which are combined together. In optional embodiments, an X-ray optic is interposed to produce a parallel beam to avoid image doubling, or the effect of image doubling is removed by software.
U.S. Pat. No. 8,503,611, whose disclosure is incorporated herein by reference, describes an X-ray topography apparatus in which X-rays diffracted from a sample which is scanned with a linear X-ray, are detected by an X-ray detector to obtain a planar diffraction image. The X-ray detector is an imaging plate shaped as a cylinder and provided with a surface area that is larger than the sample, and the imaging plate is made to undergo α-rotation about the center axis of the cylindrical shape in coordination with scanning movement of the linear X-rays. The center axis of the cylindrical shape extends in a direction at a right angle with respect to the direction of the scanning movement of the linear X-rays.
U.S. Pat. No. 8,781,070, whose disclosure is incorporated herein by reference, describes an apparatus for inspection of a disk, which includes a crystalline material and has first and second sides. The apparatus includes an X-ray source, which is configured to direct a beam of X-rays to impinge on an area of the first side of the disk. An X-ray detector is positioned to receive and form input images of the X-rays that are diffracted from the area of the first side of the disk in a reflective mode. A motion assembly is configured to rotate the disk relative to the X-ray source and detector so that the area scans over a circumferential path in proximity to an edge of the disk. A processor is configured to process the input images formed by the X-ray detector along the circumferential path so as to generate a composite output image indicative of defects along the edge of the disk.